Abstract BRS A502 is an upland rice cultivar with a medium cycle, high resistance to lodging, superior yield potential and grains of excellent industrial and cooking quality. The cultivar is indicated for crop rotation and succession in areas under intensive agriculture in the main field crop regions of Brazil.

Abstract BRS A501 CL is the first upland rice cultivar with tolerance to the broad-spectrum herbicide Kifix®. It has a medium-length cycle, high stability of whole grain yield at processing, good disease tolerance and a high grain yield.

Periodic assessment of the genetic progress made in recurrent selection programs is essential for assessing the evolution of the programs and identifying the main factors that have contributed to this progress. This study aimed to estimate genetic progress in grain yield, plant height and days-to-flowering achieved in the CNA6 population of upland rice (Oryza sativa L.), after four cycles of recurrent selection; and evaluate the genetic potential of this population to generate superior inbred lines after each selection cycle. The experimental data were obtained from progeny yield trials of each recurrent selection cycle. These trials were carried out in two or three locations per cycle, and consisted of S0:2 progenies and at least three checks. Federer’s augmented block design, with one replication on location (the environment), was adopted. Results revealed genetic progress for grain yield and plant height, with total genetic gains of 375.87 kg ha−1 and -3.90 cm, respectively, during the four selection cycles. The annual relative gain observed for grain yield was 1.54 %. The genetic potential of the population was analysed by the expected proportion of superior inbred lines. The standard adopted as the limit for obtaining superior inbred lines was the average of the checks for each trait. The genetic potential for grain yield and plant height increased during the study period. For days-to-flowering, no genetic gain occurred; however, the genetic potential of the population to generate superior inbred lines for this trait was maintained after the selection cycles.

O objetivo deste trabalho foi avaliar a possibilidade de antecipar a amostragem foliar em arroz de sequeiro, para viabilizar o diagnóstico nutricional em tempo hábil para intervenção. Foram coletadas 107 amostras foliares em ensaios de materiais genéticos da Embrapa Rondônia, no Estado de Rondônia, em três épocas de amostragem: antecipada, aos 30 e 40 dias após a semeadura (DAS); e padrão, aos 65 DAS. Foram obtidas as normas de diagnose da composição nutricional (CND) para cada época avaliada, as quais foram utilizadas para o diagnóstico em todas as épocas, tendo-se comparado os resultados do potencial de resposta à adubação sob duas ou três classes de suficiência nutricional, e verificado o grau de concordância entre os diagnósticos. O uso de duas classes de suficiência aumenta a possibilidade da antecipação da época de amostragem para diagnose foliar, o que viabilizaria o diagnóstico nutricional em tempo hábil para a correção ou a mitigação de eventuais deficiências nutricionais. A antecipação da diagnose foliar em arroz de sequeiro depende do desenvolvimento de normas de diagnose específicas para cada período amostral.

The objective of this work was to evaluate the possibility of anticipation of foliar sampling in upland rice, in order to enable nutritional diagnosis for timely intervention. One hundred and seven leaf samples were collected from genotype trials of Embrapa Rondônia, in the state of Rondônia, Brazil, in three sampling times: anticipated, at 30 and 40 days after sowing (DAS); and standard, at 65 DAS. Composition nutrient diagnosis (CND) norms were obtained for each evaluated time and used for diagnosis on all evaluation times, comparing the results from the potential response to fertilization under two or three nutritional sufficiency classes, and checking the degree of agreement between the diagnostics. The use of two sufficiency classes increases the possibility of anticipating sampling time for foliar diagnosis, which would enable timely nutritional diagnosis to correct or mitigate eventual nutritional deficiencies. The anticipation of foliar diagnosis in upland rice depends on the development of specific nutritional diagnosis norms for each sampling time.

O objetivo deste trabalho foi determinar o potencial produtivo e a interação entre genótipos e ambientes em 550 acessos da Coleção Nuclear de Arroz da Embrapa. O desempenho, a adaptação e a estabilidade produtiva de cada genótipo foram avaliados por meio da metodologia de análise dos efeitos principais aditivos e interações multiplicativas (AMMI), em nove experimentos de campo, realizados em seis Estados, em condição de sequeiro e irrigada, durante três anos agrícolas. Foi realizada a análise por meio de modelos lineares mistos, e as estimativas de componentes de variância foram obtidas pelo método de máxima verossimilhança residual (REML), com aplicação do procedimento de melhor predição linear não viesada (BLUP) para a predição dos valores genéticos dos efeitos aleatórios (EBLUP) associados a cada um dos acessos. O grupo de acessos com melhor desempenho foi o de linhagens e cultivares brasileiras (LCB), conforme o esperado. No entanto, foram identificadas variedades tradicionais (VT) entre os genótipos mais produtivos, o que mostra o potencial deste grupo de germoplasma em contribuir com novas fontes de variabilidade genética para programas de melhoramento. Foram identificados acessos superiores quanto à estabilidade, adaptabilidade e produtividade de grãos, entre os quais destacam-se CA880078, CA840182 e CNA00091.

The objective of this work was to determine the productive potential and the genotype by environment interaction of 550 accessions of the Embrapa's Rice Core Collection. The performance, and yield adaptability and stability of each genotype was evaluated using the additive main effects and multiplicative interactions (AMMI) approach, in nine field experiments, carried out in six Brazilian states, under dry and irrigated conditions, during three years. The linear mixed model analysis was performed, and the estimates of the variance components were obtained by the residual maximum likelihood (REML), using the best linear unbiased prediction (BLUP) procedure for the prediction of the genotypic values of random effects (EBLUP) associated with each accession. The group of accessions with better performance was the one of lines and cultivars from Brazil (LCB), as expected. However, traditional varieties (VT) were identified among the best yielding genotypes, which shows the potential of this germplasm group to contribute as a new source of genetic variability to breeding programs. Superior accessions were identified for their stability, adaptability and grain yield, among which CA880078, CA840182 and CNA00091 stand out.

Este trabalho teve o objetivo de avaliar o desempenho, a estabilidade e a adaptabilidade de 21 cultivares de soja (Glycine max (L.) Merrill), em cinco épocas de plantio no cerrado de Rondônia. O delineamento experimental foi blocos ao acaso, com três repetições. Os ensaios foram conduzidos no ano de 1996/97 pelo Centro de Pesquisa Agroflorestal de Rondônia, no Campo Experimental de Vilhena em Rondônia, RO. Os métodos utilizados apresentaram concordância entre os resultados alcançados, sendo que o comportamento das cultivares nas diferentes épocas de semeadura pode ser representado por um modelo linear. O coeficiente de resposta linear beta1i não apresentou diferença significativa (P<0,05) da unidade pelo teste t (beta1i = 1) em todas as cultivares testadas. As cultivares que apresentaram desvios de regressão sigma²(d i) significativos (P<0,05) foram MT/BR50 e EMBRAPA 31, com R² = 58,56% e 74,43%, respectivamente. As demais cultivares não apresentaram desvios de regressão significativos.

The objetive of this study was to evaluate the stability and adaptability of soybean (Glycine max (L.) Merrill) cultivars in five different planting dates. The tests were composed by 21 cultivars outlined in a random blocks design, with three replicates, conduced in 1996/97 by Embrapa-Centro de Pesquisa Agroflorestal de Rondônia, in a field of Vilhena, RO, Brazil. The used methods showed accordance between the achieved results, being the behavior of cultivars in different times of sowing represented by a linear model. The coefficient of linear regression beta1i did not show any significant difference of the unit by the t test for all the tested cultivars (P<0.05). The cultivars which presented significant regression deviation sigma²(d i) (P<0.05) were MT/BR50 e EMBRAPA 31, R² = 58.56% e 74.43%, respectively. The other cultivars did not present any significant regression deviation.

Conduziu-se experimento objetivando descrever sintomas visuais de deficiências de macronutrientes em estévia (Stevia rebaudiana) e avaliar seus efeitos no crescimento, composição química e produção de esteviosídeo. Os sintomas foram: clorose generalizada, com -N; folhas verde-escuras, com -P; folhas com clorose, bronzeamento e necrose, com -K; necrose de ápices, com -Ca; clorose e necrose foliar, em "V" invertido, com -Mg e folhas verde-pálidas e menores, com -S. As deficiências de N, K e Mg reduziram o crescimento das folhas e a parte comercializável da planta, enquanto que a deficiência de Mg promoveu acentuada redução no desenvolvimento do sistema radicular. As deficiências de N, P, K e S diminuíram a relação entre matéria seca da parte aérea e das raízes, enquanto a deficiência de Mg aumentou-a. Todas as deficiências causaram a diminuição na absorção de macronutrientes, exceto a de Ca, que reduziu somente a absorção de Ca, e a de K, que não alterou as absorções de Mg e S. A composição química dos cinco últimos pares de folhas totalmente expandidas representou bem o estado nutricional da planta. As deficiências de K, Ca e S reduziram somente o teor de esteviosídeo, enquanto todas as deficiências, exceto a de P, diminuíram o conteúdo de esteviosídeo.

This experiment was carried out to describe visual symptoms of macronutrients deficiencies in Stevia rebaudiana, and the effects of these deficiencies on growth, chemical composition and stevioside production. The symptoms were: yellowing with -N; dark green leaves with -P; clorotic, mottled, and necrotic leaves, with -K; apical necrosis, with -Ca; leaves with clorosis and necrosis in inverted "V" shape, with -Mg, and small pale green leaves, with -S. N, K, and Mg deficiencies reduced the leaf growth, therefore the plant marketable part. Mg deficiency caused greater reduction on the development of the radicular system. N, P, K, and S deficiencies decreasead the shoot:root dry weigth ratio, while Mg deficiency increased it. All deficiencies decreased the absorption of macronutrients, except of Ca, which reduced only the absorption of Ca, and K, that did not affect the absorption of Mg and S. The chemical content of the last five fully expanded leaf pairs showed good correlation with the plant nutritional status. The deficiencies of K, Ca, and S decreased the concentration of stevioside while all deficiencies, except of P, decreased the stevioside content.